The scripting capability is fantastic for making small (an big) tweaks to the app. It is especially useful for controlling what a user can and cannot see such as tabs and fields. This should be controllable by privilege - and it is - but it there is no easy way to get new custom privs into the app (there is a hack but I won't describe that here).
Take for example this script that controls whether or not the user can see a specific tab on the Customer W.B. based on a new priv. The priv has to be added manually with a SQL statement (commented out) but should be able to do so with a new screen that provides this capability. - and of course is controlled by a new priv!
// INSERT INTO
// 'Script: Can View A/R Tab on Cust W.B.');
Steps to reproduce:
Read more at http://www.xtuple.org/mantis/view.php?id=8452